Yankee dryer having centrifugally assisted condensate collection

Abstract

A Yankee dryer which exploits centrifugal forces to assist in evacuating condensate. A condensate collection system has individual pickup straws arranged at an angle such that the required amount of motive steam pressure is reduced to extract and move the steam condensate from the intake opening of the straw to the discharge point of that straw. The pickup straws communicate with a collection header arranged along the length of the Yankee dryer. The collection header is configured such that it has a radius from the axis of rotation which is greatest near the point at which collected condensate is discharged to a disposal riser conduit which conducts collected condensate to the exterior of the Yankee dryer.

I claim: 
     
         1 . A Yankee dryer having centrifugally assisted condensate collection, comprising:
 a cylindrical drum having a circumferential wall, a first end wall, a second end wall, an axis of rotation, radial distances originating at the axis of rotation, a mainstay disposed to position the cylindrical drum relative to an environmental support; and   at least one condensate disposal system comprising a collection header extending in a direction parallel to the axis of rotation, a plurality of pickup straws projecting laterally from and disposed in fluid communication with the collection header and comprising a pickup opening which opens to the interior of the cylindrical drum and a discharge opening which opens to the interior of the collection header, and a disposal riser conduit disposed in fluid communication with the collection header and arranged to extend to the axis of rotation and along the axis of rotation to the first end wall and from the first end wall to the exterior of the cylindrical drum, wherein   the pickup opening of each one of the pickup straws is located at a first radius from the axis of rotation and the discharge opening of each one of the pickup straws is located at a second radius from the axis of rotation which said second radius is greater in magnitude than the first radius.   
     
     
         2 . The Yankee dryer of  claim 1 , wherein each one of the pickup straws has a center line and the disposal riser conduit has a center line forming an included angle with the center line of any one of the straws, and the included angle between the center line of any one straw and the center line of the disposal riser conduit lies within a range of about eighty degrees and about ninety degrees. 
     
     
         3 . The Yankee dryer of  claim 1 , wherein the collection header has opposed ends, and the outer wall of the collection header inclines continuously along its length relative to the axis of rotation of the cylindrical drum such that the radial distance from the axis of rotation to the inner surface of the outer wall of the collection header is greatest at the location of the pickup opening of the disposal riser conduit and is smallest at the opposed ends of the collection header. 
     
     
         4 . The Yankee dryer of  claim 1 , wherein the outer wall of the collection header and the circumferential wall of the cylindrical drum each have length which is oriented parallel to the length of the other, and wherein the outer wall of the collection header and the circumferential wall of the cylindrical drum form an included angle therebetween along the lengths of the collection header and of the circumferential wall, wherein the included angle is between 0.1 degree and about ten degrees. 
     
     
         5 . The Yankee dryer of  claim 1 , wherein the collection header abuts the circumferential wall of the cylindrical drum. 
     
     
         6 . The Yankee dryer of  claim 1 , wherein the at least one condensate disposal system comprises at least two condensate disposal systems. 
     
     
         7 . The Yankee dryer of  claim 6 , wherein the disposal riser conduit of one of the condensate disposal systems joins the disposal riser conduit of another one of the condensate disposal systems at the axis of rotation to form a singular conduit extending along the axis of rotation. 
     
     
         8 . A Yankee dryer having centrifugally assisted condensate collection, comprising:
 a cylindrical drum having a circumferential wall, a first end wall, a second end wall, an axis of rotation, radial distances originating at the axis of rotation, a mainstay disposed to position the cylindrical drum relative to an environmental support; and   at least one condensate disposal system comprising a collection header extending in a direction parallel to the axis of rotation, a plurality of pickup straws projecting laterally from and disposed in fluid communication with the collection header, each one of the pickup straws having a pickup opening which opens to the interior of the cylindrical drum and a discharge opening which opens to the interior of the collection header, and a disposal riser conduit disposed in fluid communication with the collection header and arranged to extend to the axis of rotation, along the axis of rotation to the first end wall, and from the first end wall to the exterior of the cylindrical drum, wherein the disposal riser conduit has a pickup opening disposed in fluid communication with the collection header and a discharge opening, wherein   the collection header has an outer wall facing the circumferential wall of the cylindrical drum arranged such that the inner surface of the outer wall of the collection header has a radial distance from the axis of rotation of the cylindrical drum which is greater at the pickup opening of the riser conduit than at any other point along the length of the collection header.   
     
     
         9 . The Yankee dryer according to  claim 8 , wherein the collection header has opposed ends, and the outer wall of the collection header inclines continuously along its length relative to the axis of rotation of the cylindrical drum such that the radial distance from the axis of rotation to the inner surface of the outer wall of the collection header is greatest at the location of the pickup opening of the riser conduit and is smallest at the opposed ends of the collection header. 
     
     
         10 . The Yankee dryer of  claim 9 , wherein the outer wall of the collection header and the circumferential wall of the cylindrical drum each have length which is oriented parallel to the length of the other, and wherein the outer wall of the collection header and the circumferential wall of the cylindrical drum form an included angle therebetween along the lengths of the collection header and of the circumferential wall, wherein the included angle is between 0.1 degree and about ten degrees. 
     
     
         11 . The Yankee dryer of  claim 8 , wherein the collection header abuts the circumferential wall of the cylindrical drum. 
     
     
         12 . The Yankee dryer of  claim 8 , wherein the at least one condensate disposal system comprises at least two condensate disposal systems. 
     
     
         13 . The Yankee dryer of  claim 12 , wherein the riser conduit of one of the condensate disposal systems joins the riser conduit of another one of the condensate disposal systems at the axis of rotation to form a singular conduit extending along the axis of rotation. 
     
     
         14 . A method of equipping different types or models of Yankee dryers, comprising the steps of:
 fabricating condensate disposal system modules to only one design;   installing at least two of the identical condensate disposal system modules in a particular Yankee dryer;   installing other ones of the identical condensate disposal system modules in a different Yankee dryer; and   installing identical condensate disposal system modules in any one Yankee dryer in proportion to the condensate production rate of the one Yankee dryer.